Regulator



Dec. 16, 1930. L. w. THOMPSON REGULATOR Filed Aug. 26, 1929 a E 3 V\\= 2 M v m a w l 4 0 20 f w w%@ s n r a: th t A VW 5 mm w W Patented Dec. 16, 1930 UNITED STATES PATENT OFFICE LOUIS W. THOMPSON, OF SCHENECTADY, NEW YORK, ASSIGNOR T0 GENERAL ELEC- TRIO COMPANY, A CORPORATION OF NEW YORK REGULATOR Application filed August 26, 1929. Serial No. 388,357.

My invention relates to regulators and more particularly to electrical regulators for controllin an electrical condition of a circuit or a dynamo electric machine.

Regulators of the type wherein the field current or voltage of a regulated machine is automatically changed in response to changes in an electrical condition of said machine in such a manner as to tend to maintain said condition constant, are inherently prone to hunt. This has necessitated the use of anti hunting means, usually including a coil connected to the field of the regulated machine in such a manner that its effect is to oppose the change in field current or voltage. The use of such means has however the effect of producing what in a voltage regulator would be called under-compounding. Thus as the field voltage is increased in order to raise the voltage of a regulated generator, in response to a drop in generated voltage occasioned by an increase in load, for example, the antihunting coil will increasingly oppose the raising of the field voltage, which effectually prevents the voltage of the generator from ever returning to normal so long as the increased load remains. Such a result, being contrary to the pur ose of the regulator, is obviously objectiona le.

It is an object of my invention to provide an improved regulator and more particularly to rovide improved means for eliminating under-compounding in an electrical regulator employing anti-hunting means.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Referring now to the single figure of the drawing which is a diagrammatic representation of my invention, 1 is a three-phase alternator having an armature 2 connected to a distribution circuit 3 and a field winding 4 connected to an exciter 5. It is to be noted that my'invention is not limited in its application to alternators but obviously is equally applicable to direct current generators, whether separately excited or not. The exciter 5 has an armature 6 and a shunt field winding 7, in whose circuit is a rheostat 8 comprising a resistance 9 connected at intervals to contacts 10 over which rolls an arcuate contact 11 having an arm 12 pivoted at 13 to a solenoid plunger 14. Surrounding plunger 14 is an operatin coil 15 connected to be responsive to the voltage of the distribution circuit 3, although it will occur to those skilled in the art that it might equally well be connected to be responsive to the current traversing the distribution circuit 3 if constant current rather than constant voltage is to be maintained. The characteristics of plunger 14 and coil 15 are similar to those of the alternating current coil and plunger assembly of the well known Tirrill type regulator in that there is a considerable range of positions of plunger 14 for a given current in coil 15 and this current is the current flowing in the coil when the line voltage at the point where the coil is connected to the line is the voltage which the regulator is designed to hold constant. A slight increase or decrease in current through coil 15 causes plunger 14 to move up or down respectively. Connected across the exciter 5 is an antihunting coil 16 surrounding plunger 17. Plungers l4 and 17 are connected by a dash pot 18. The lower end of plunger 17 is pivotally connected to arm 19, which in turn is pivoted at 20. To the right hand end of arm 19 are connected a plurality of springs 21, whose tensions are adjustable by means of turn screws 22. These springs serve to-balance the pull of coil 16 on plunger 17. Resistances 23 and 24 are connected in the circuits of coils 15 and 16 respectively so as to reduce the currents therethrough and consequently the heating losses.

The operation of the embodiment of my invention illustrated in the drawing is as follows Assuming that theload on generator 1 should increase, its terminal voltage would decrease. This in turn causes a decrease in current hrough coil 15 allowing plunger 4 to drop, although its motion will be retarded somewhat by dash pot 18. The lowering of plunger 14 causes contact 11 to roll in such a way over contacts 10 that the resistance in the field circuit of exciter 5 is decreased, hence increasing the exciter voltage, generator field cu"rent and generator voltage respectively. As soon as the generator voltage rises to its former value, plunger 15 comes to rest and the rise in voltage is checked. Before this occurs, however, the increase in current thr ugh the anti-hunting coil, as a result of the increased exciter voltage, causes plunger 17 to rise, which produces an additional retarding effect on the downward motion of plunger 14, although allowing the latter to eventually fall far enough to bring the generator voltage back to its former value. It will thus be seen that the dashpot 18 only allows the anti-hunting means to affect the position of plunger 14 for a short time, after which both plungers 14 and 17 will. be in a state of independent static equilibrium until another voltage change takes place on circuit 3. If plungers 14 and 17 were directly connected together however the tendency of plunger 17 to rise as the exciter voltage rises would prevent plunger 14 from ever dropping far enough to maintain the generator yoltage at its former value, so that the plungers would be in a state of dependent static equilibrium rather than in a state of independent static equilibrium. JThe operation of the system when the generator voltage rises will of course be such as to cause the plungers to move away from each other and tend to maintain the voltage constant.

While I have shown and described a particular embodiment of my invention it will be obvious to those skilled in the art that changes and modifications may be made without departing from my invention and I therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, a distribution circuit, a dynamo electric machine connected to said circuit, a variable resistance type regulator for said dynamo electric machine, said regulator having an operating means connected to be responsive to changes in an electrical condition of said distribution circuit, and an anti-hunting means connected to be responsive to an electrical condition of the field circuit of said dynamo electric machine, and a yielding connection having a time element function between said operating means and said anti-hunting means whereby said operating means and said anti-hunting means are normally in a state of independent static equilibrium.

2. In combination, a dynamo electric machine, a variable resistance type regulator for said dynamo electric machine, said regulator including an operating means mechanically connected to an anti-hunting means, said anti-hunting means being connected to be responsive to variations in the excitation of said machine and means for preventing under-compounding of said regulator comprising a vielding means having a time delayed action inserted in the mechanical connection between said operating means and said anti-hunting means whereby said operating means and said anti-hunting means are normally in a state of independent static equilibrium.

3. In a variable resistance type voltage regulator for a dynamo electric machine, means responsive to changes in the voltage of said. machine for varying the field voltage thereof in substantially a continuous manner so as to producecompensatory changes in the voltage of said machine, means responsive to variations in field voltage of said machine, means mechanically connecting both of said means so that said last mentioned means opposes the action of said first mentioned means, said connecting means including yielding means having a time delayed action.

4. In combination, a dynamo electric machine, an exciter for the field of said ma chine, a resistance in the field circuit of said exciter, means responsive to changes in an electrical condition of said machine for varying the magnitude of said resistance in a substantially continuous manner in such a way as to tend to maintain said electrical condition at a predetermined state, means responsive to changes in exciter voltage for opposing the action of said first mentioned means, and a yielding connection having a time delayed action between said two means.

5. In combination, a dynamo electric ma.- chine, a regulator associated therewith comprising a variable resistance, means connecting said resistance to said machine so that variations in the magnitude of the former will produce variations in the excitation of said machine, electromagnetically operated means for varying the magnitude of said resistance in proportion to the tendency of an electrical condition of said machine to depart from a predetermined value in such a manner as to maintain said condition substantially constant, electromagnetically operated means connected to be responsive to variations in the excitation of said machine, resilient means for opposing the action of said excitation responsive means, and yielding means having a time delayed action for mechanically connecting said resistance varying means and said excitation responsive means.

In witness whereof I have-hereunto set my hand this 24th day of August, 1929.

LOUIS W. THOMPSON. 

